Optoelectronic semiconductor device

ABSTRACT

An optoelectronic or photosensitive semiconductor device in which a light-emitting element and a light-responsive element are arranged in a common casing, the degree of photocoupling between the two elements being dependent entirely on conditions exterior of the casing. In one embodiment, the two elements are embedded in a light-permeable mass, the boundary surface of which, together with a medium surrounding the mass, forms a surface whose reflection characteristic is dependent on the indices of refraction of the mass and of the medium, the elements themselves being so arranged that when the index of refraction of the medium is such that the boundary reflects the light coming from the light-emitting element, the reflected light is picked up by the light-responsive element, with the amount of light being picked up being dependent on, and thus an indication of, the medium surrounding the mass. In another embodiment, light emitted by the light-emitting element is free to exit the mass and, if reflected by an object outside the mass, is picked up by the lightresponsive element.

United States Patent Zizelmann r [54] OPTOELECTRONIC SEMICONDUCTOR [73]Assignee: Telelunken Patenverwertungsgesellschaft mbH, Ulm (Danube),Germany 221 Filedz Sept. 23, 1968 211 Appl.No.: 761,685

[30] Foreign Application Priority Data Sept. 27, 1967 Germany ..T 34891[52] US. Cl ..250/218, 250/239, 340/234, 340/237 R, 340/244 R, 356/133,356/136 [5|] lnt. Cl. ..G0ln 2l/26,G01n 21/46, G02b 21/00, v .HO 1 j39/02 [58] Field of Search ..250/239, 218;356/135,133;'

[56] References Cited UNITED STATES PATENTS 2,350,712 6/1944 Barsties..250/218 X 2,355,014 8/1944 Schom ..340/234 51 3,639,770 1 1 Feb. 1,1972 3,426,211 2/ 1969 Anderson ..250/218 OTHER PUBLICATIONS Freeman-IBM Technical Disclosure Bulletin, Vol. 5, No. 1, June 1962 PrimaryExaminerRoy Lake Assistant Examiner-V. Lafranchi Attorney--Spencer &Kaye [5 7] ABSTRACT An optoelectronic or photosensitive semiconductordevice in which a light-emitting element and a light-responsive elementare arranged in a common casing, the degree of photocoupling between thetwo elements being dependent entirely on conditions exterior of thecasing. In one embodiment, the two elements are embedded in alight-permeable mass, the boundary surface of which, together with amedium surrounding the mass, forms a surface whose reflectioncharacteristic is dependent on the indices of refraction of the mass andof the medium, the elements themselves being so arranged that when theindex of refraction of the medium is such that the boundary reflects thelight coming from the light-emitting element, the reflected light ispicked up by the light-responsive element, with the amount of lightbeing picked up being dependent on, and thus an indication of, themedium surrounding the mass.

2,359,787 10/1944 Facts et 1n another embodiment, light emitted by thelight-emitting 9 3 3/1961 MFKeag 340/234 X element is free to exit themass and, if reflected by an object 3,167,658 1/1965 Richter ..250/239outside he mass, is picked up by h ghbmsponsivc demon; 3,227,929 1/1966McCreight ..250/239 X 3,282,149 1 1/1966 Shaw et a1 ..356/133 X 7Claims, 4 Drawing Figures PATENIEBFE! 11912 3,639,770

sum 1 nr 2 Fig. I

mveuron Walter Zizelmann ATTORNEYS rmmsum um 31639310 SHIEI 2 OF 2 vINVENTOR Walter Zizelmonn aY M ATTORNEYS BACKGROUND OF THE INVENTIONThere exist various types of photosensitive devices by means of whichthe absence or presence of various types of objects can be determined.Such devices include a lightemitting element and a light-responsiveelement, which must be strategically placed so that the light going fromthe former to the latter will follow a path which cuts across the spaceoccupied by the object the presence or absence of which is to bedetermined. This creates a number of difficulties, not only insofar asthe placement of the elements is concerned, but also insofar asmanufacturing and installation costs are concerned.

It is, therefore, the-object of the present invention to provide a wayin which to overcome the above drawbacks.

BRIEF DESCRIPTION OF THE INVENTION With the above object in view, thepresent invention relates to an optoelectronic semiconductor devicehaving a lightemitting element as well as a light-responsive element,the two elements being arranged in a common light-permeable'casing insuch a way as to make possible the determination of a characteristic ofthe medium surrounding the casing, or of an object next to the casing,from the degree of the optoelectronic coupling between the two elements-H Thanks to the fact that, in accordance with thepresent invention andin contradistinction to the known prior art, the light source as well asthe light receiver or pickup are accommodated in a common housing, themanufacture and construction of indicator apparatus incorporatinglight-responsive elements is significantly simplified and the cost andinstallation of this type equipment, which is generally used forrecording and counting, is reduced.

"More particularly, the present invention resides in a photosensitivedevice in which the light-emitting and lightresponsive elements areembedded in a common light-permeable casing, the elements being soarranged that the amount of light picked up by the light-responsiveelement is dependent on'conditions which are entirely exterior ofthecasing.

' According to one embodiment of the present invention, the elements areembedded in a mass, the boundary surface between the mass and-the mediumsurrounding the mass forminga surface whose reflection characteristic isdependent on the indices of refraction of the mass and of the medium,the index of refraction of the mass being so selected and the elementsbeing so arranged that when the medium outside the massis gaseous, lightemitted by the light-emitting element is reflected by the boundarysurface so as to strike the light-sensitive element, whereas, when themedium is a liquid, virtually none of the light is reflected. Inpractice, the amount of light whichis reflected will depend on the indexof refraction of the liquid. 7

According to another embodiment, the light emitted by the light-emittingelement exits from the light-permeable mass but is picked up. ifreflected by an opaque object outside of the mass.

Thanks to the above arrangement, the type of medium surroundingthecasing, or the presence of an object outside of the casing, ca n bedetermined and the device can be used, for example, to respond to andcontrol a liquid level in that the output obtained from thelight-responsive element will depend on whether or not, and how much,light strikes this element.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are sectional views ofone embodiment of a device according to the present invention which issuitable for indicating and controlling liquid levels, the two figuresshowing the operation of the device when the same is surrounded by twodifferent media.

FIGS. 3 and 4 are sectional views of another embodiment of a deviceaccording to the present invention, the two figures showing theoperation of the device when used for counting and recording passingobjects.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to thedrawings and first to FIG. I thereof, the same shows a semiconductordevice comprising a socket 1, through which extend three electrode leads2, 3, 4, which are electrically insulated from the socket and from eachother, there being a fourth electrode lead 5 which is electricallyconductively connected to the metallic bottom of the socket l. The lead3 is shown as extending upwardly beyond the bottom of the socket, therebeing a light-responsive element 6 arranged at the top of lead 3, oneelectrode of this element 6 being electrically connected with the top ofthe lead 3. This element 6 is, for example, a silicon photodiode orphotoresistor, whose other electrode is connected, by way of a thinconnecting wire 7, with one of the other lead, such as the lead 2 asshown in FIG. 1. If desired, the connecting wire 7 can be dispensed withby extending the lead 2 upwardly and by bending the ends of leads 2 and3 in such a way that the lightresponsive element 6 is between the endsof the two leads and is thus electrically connected to both. In anyevent, the lightresponsive element is located generally above the centerof the socket.

A light-emitting element 9, for example, a gallium-arsenideluminescence-type diode, is arranged in the region of the edge of thebottom surface'S of the socket and has one of its electrodeselectrically connected with another of the leads, e.g., the lead 5 asshown, the other electrode of the element 9 being connected to thefourth lead 4 via a further connecting wire 70.

The socket l as well as the electrode connections and the semiconductorelements 6 and 9 are embedded in a lightpermeable mass 10, such asglass, synthetic resin, or a mixture of the two. This light-permeablemass 10 thus forms a closed casing and, as shown in FIG. 1, has aconical configuration which enlarges in the direction from the top, asviewed in FIG. 1, toward the socket.

If, now, the element 9 is excited by means of an electric currentflowing therethrough, the element will emit a beam of light 11, whichwill strike the boundary surface 13 between the light-permeable mass 10and the surrounding medium 12 at a .very large angle of incidence (thisbeing the angle between the light beam and the perpendicular to theboundary surface at the point of incidence), namely, an angle ofincidence which is but slightly less than If the medium 12 surroundingthe casing 10 is a gaseous medium, the angle of incidence will begreater than the critical angle and the entire light beam 13 will bereflected atthe boundary surface 13 and .will impinge on thelight-sensitive layer of the element 6, the

precise position of which is such as to be in the path of light emittedby element 9 and reflected by the boundary surface 13. Thus, thelight-sensitive characteristic of the element 6 will be markedlyaffected by the large amount of light which strikes the element 6 whenthe device is surrounded by a gaseous medium.

If, however, the device is immersed in a liquid as shown in FIG. 2, theangle of incidence will be less than the critical angle and the boundarysurface 13 between the casing 10 and the medium 12 will not reflect thelight beam 11; instead, the same will freely exit the mass and passthrough the boundary surface 13 and into the liquid medium. The element6 is thus not subjected to illumination emanating from the element 9.

It will thus be seen that whether or not the arrangement is in a liquidcan bedetermined by measuring the characteristic of the element 6, sincethis characteristic will be markedly different depending on whether thecasing 10 is surrounded by a gaseous or a liquid medium. This can bedone electrically, via the leads 2 and 3, in a manner well known in theart. The electrical output of this measurement can then be used to givean indication of the height of a liquid level, or for controllingswitching systems, pumps, motors, or the like, for example, for thepurpose of controlling a liquid level under various conditions, such asin washing machines, in fountains, or in storage tanks containing water,gasoline, oil, or any other liquid.

In the preceding discussion, it was assumed that the liquid is a clearliquid. If, however, the liquid is not clear but a lightdispersing suchas milk, some of the light emanating from the element 9 will strike theelement 6. The amount of this light will depend on the opaqueness orcloudiness of the liquid, so that the characteristic of the element 6can be used as a measure of the light-dispersing characteristic of theliquid. Thus, the purity or cloudiness of the liquid surrounding thecasing 10 can be determined, as this will affect the light sensitivecharacteristic of element 6.

The following is an illustrative and not limitative example of theembodiment described above. The light-responsive element 6 is a silicondiode, and the element 9 is a GaAs luminescence diode. The mass 10 ismade of epoxy resin and has an index of refraction of about 1.5. Innormal operation the excitation current applied to element 9 is 100 m.A.DC. When the arrangement is surrounded by air and the maximum light fromelement 9 is reflected by the boundary surface 13 to impinge on element6, the output current is 9 uA.; when the arrangement is submersed inclear water, the output current of element 6 is l uA. With thearrangement being submersed in milk, there was obtained an output fromelements 6 of 13 ,LA.; in water with a milk content of 10 percent, theoutput was 2 uA.; in water with a milk content of 50 percent, the outputwas 7 uA.; in oil and in gasoline, the output was the same as in water(about 1 p.A.).

FIG. 3 shows another embodiment of a device according to the presentinvention wherein both the light-emitting and the light-responsiveelements 9' and 6', which may again be constituted by a gallium-arsenideluminescence diode and a silicon photodiode, respectively, each havingone of their electrodes in direct electrical contact with the bottomsurface 8 of the socket 1. The two elements 6, 9', are arrangedgenerally in the center of the bottom surface, the same normally beingcircular. In this embodiment, the lead is electrically connected withthe socket while the other two leads, namely 2' and 3', are insulatedfrom the socket and contact the other electrodes of the twosemiconductor elements, respectively. The light-permeable mass 10', inwhich the other components are embedded or which, if made of resin, maybe molded to the other components, is shown as arching upwardly in asubstantially hemispherical configuration.

lf, now, as shown in FIG. 3, the element 9' is excited and puts out alight beam 11, the same strikes the spherical boundary surface 14between the mass 10 and the surrounding medium 12normally air-atpractically a right angle, so that if there is nothing near the devicewhich would reflect the light, the element 6' will receive virtually nolight. If, however, an opaque object 15 is moved past the arrangement inthe direction of the arrow 150, as shown in FIG. 4, a portion 16 of thelight beam 11' is reflected and will strike the element 6', whichresponds by changing its characteristic as the result of the impinginglight. ln this way, the passage of an article can be noted, the outputsignal of the device being applied to any suitable recording apparatusor counter, or otherwise be processed to utilize the information.

in both the above-described device as well as in that described inconnection with FIGS. 1 and 2, the light emitting element can beenergized to emit alternating light, so as to make the device asindependent as possible from ambient light conditions.

The following is an illustrative and not limitative example of theembodiment described in connection with FIGS. 3 and 4, the sameincorporating similar light-emitting and light-sensitive elements and asimilar light-permeable mass as that which described in conjunction withthe specific example of the embodiment of FIGS. 1 and 2. When no lightfrom element 9 was reflected on element 6', the output of the latter was100 A; when an opaque plate was passed within a distance from theelement of approximately 0.5 mm., sufficient light was reflected ontothe element 6 to obtain from it an output of 300 ,uA.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations. For example, the precise spatial location of thelight-emitting and light-responsive elements can be varied, as can theshape and composition of the lightpermeable mass, and the number ofleads, the latter depending on whether the elements will have a commonlead and/or the number of electrodes of the elements. For instance, ifthe light-sensitive element is a phototransistor instead of a diode, anadditional lead will be provided.

The terms light-emitting, "light-responsive" and lightpermeable" as usedthroughout the instant specification and claims, are intended tocomprehend not only visible light but also invisible light and otherradiation having characteristics which are technologically andscientifically equivalent to light radiations.

lclaim:

1. An optoelectronic semiconductor device comprising, in combination:

a. a radiation-permeable mass selected from the group consisting ofresin, glass, and a mixture of resin and glass, and constructed in theform of a closed casing having a hemispherical or conical configurationhaving an index of refraction and defining an outer boundary surface.

. a radiation-emitting gallium-arsenide luminescence-type diode embeddedin said mass and arranged to emit a beam of radiation at an angle ofincidence with respect to said boundary surface which is less than thecritical angle at said boundary surface when said boundary surface issurrounded by a liquid medium to permit substantially all of theradiated beam to freely exit from said mass, and greater than thecritical angle at said boundary surface when said boundary surface issurrounded by a gaseous medium to reflect substantially all of theradiated beam as a function of the index of refraction of said gaseousmedium;

c. a radiation-responsive semiconductor element embedded in said massand arranged in the path of radiation reflected from said boundarysurface to receive same; and

d. a socket connected to said mass which mass enlarges toward saidsocket, and leads extending through said socket and connected to theradiation emitting diode and the radiation-responsive element, theradiation emitting diode being arranged on said socket and saidradiation responsive semiconductor element being spaced from said socketand supported on one end of one ofsaid leads, which lead extends beyondsaid socket and into said mass.

2. An optoelectronic semiconductor device comprising, in combination:

a. a radiation-permeable mass forming a closed hemispherical casing;

b. a radiation-emitting gallium-arsenide luminescence diode embedded insaid mass near the center of said hemispherical casing and arranged toemit radiation which exits from said mass without being reflected;

c. a radiation-responsive silicon photodiode embedded in said mass nearthe center of said hemispherical casing and adjacent theradiation-emitting diode and arranged to receive radiation emitted bysaid radiation-emitting diode and reflected by striking an opaque objectto be detected outside of said mass; and

. a socket connected to said mass and having a bottom surface on whichsaid diodes are mounted, which mass enlarges toward said socket, andleads extending through said socket and connected to said diodes.

3. An optoelectronic semiconductor device comprising, in combination;

a. a radiation-permeable mass forming a closed casing;

b. a radiation-emitting element embedded in said mass;

c. a radiation-responsive element embedded in said mass for receivingradiation emitted by said radiation-emitting element and reflected backinto the mass; and

spherical or conical.

6. A device as defined in claim 3 wherein said radiationemitting elementis a gallium-arsenide luminescence-type diode.

7. A device as defined in claim wherein said radiationresponsive elementis a silicon photodiode, a phototransistor, or a photoresistor UNITEDSTATES- PATENT OFFICE CERTIFICATE OF CORR'ECTKON P t n N 3,639 .770Dated Februarv 1st, 1972 lnventol-(s) Walter Zizelmann It is certifiedthat error appears in the above-identifiedpatent and that; said LettersPatent, are hereby corrected as shown below:

In the heading of the patent, line 4, change"Patenverwertungsgesellschaft." to --Patentverwertungsgesellschaft-. Column 2, line 60,change 11" to -ll'-.

Signed and sealed this 8th day of August 1972.

(SEAL) Attest:

EDWARD I*I.FLETCBER ,JR. ROBERT GOTTECI-IALK Attesting QfiicerCommissioner of Patents FORM PO-1050 (10-69) uscowwtpz 60376-P69 9 U S.GOVERNMENY PRINTING OFFICE 1969 O-36633-l

1. An optoelectronic semiconductor device comprising, in combination: a.a radiation-permeable mass selected from the group consisting of resin,glass, and a mixture of resin and glass, and constructed in the form ofa closed casing having a hemispherical or conical configuration havingan index of refraction and defining an outer boundary surface. b. aradiation-emitting gallium-arsenide luminescence-type diode embedded insaid mass and arranged to emit a beam of radiation at an angle ofincidence with respect to said boundary surface which is less than thecritical angle at said boundary surface when said boundary surface issurrounded by a liquid medium to permit substantially all of theradiated beam to freely exit from said mass, and greater than thecritical angle at said boundary surface when said boundary surface issurrounded by a gaseous medium to reflect substantially all of theradiated beam as a function of the index of refraction of said gaseousmedium; c. a radiation-responsive semiconductor element embedded in saidmass and arranged in the path of radiation reflected from said boundarysurface to receive same; and d. a socket connected to said mass whichmass enlarges toward said socket, and leads extending through saidsocket and connected to the radiation emitting diode and theradiationresponsive element, the radiation emitting diode being arrangedon said socket and said radiation responsive semiconductor element beingspaced from said socket and supported on one end of one of said leads,which lead extends beyond said socket and into said mass.
 2. Anoptoelectronic semiconductor device comprising, in combination: a. aradiation-permeable mass forming a closed hemispherical casing; b. aradiation-emitting gallium-arsenide luminescence diode embedded in saidmass near the center of said hemispherical casing and arranged to emitradiation which exits from said mass without being reflected; c. aradiation-responsive silicon photodiode embedded in said mass near thecenter of said hemispherical casing and adjacent the radiation-emittingdiode and arranged to receive radiation emitted by saidradiation-emitting diode and reflected by striking an opaque object tobe detected outside of said mass; and d. a socket connected to said massand having a bottom surface on which said diodes are mounted, which massenlarges toward said socket, and leads extending through said socket andconnected to said diodes.
 3. An optoelectronic semiconductor devicecomprising, in combination; a. a radiation-permeable mass forming aclosed casing; b. a radiation-emitting element embedded in said mass; c.a radiation-responsive element embedded in said mass for receivingradiation emitted by said radiation-emitting element and reflected backinto the mass; and d. a socket connected to said mass and having abottom surface on which at least said radiation-emitting element ismounted, which mass enlarges toward said socket, and leads extendingthrough said socket and connected to said elements.
 4. A device asdefined in claim 3, wherein said radiation-responsive element is mountedon said bottom surface.
 5. A device as defined in claim 3 wherein saidmass is hemispherical or conical.
 6. A device as defined in claim 3wherein said radiation-emitting element is a gallium-arsenideluminescence-type diode.
 7. A device as defined in claim 3 wherein saidradiation-responsive element is a silicon photodiode, a phototransistor,or a photoresistor.